The present invention relates to an apparatus for raising small animals as used in experiments, and more particularly to a rack device for mounting cages for confining small animals.
Conventional rack devices for raising small animals have various disadvantages which are known in the prior art. For example, the frame for the rack device usually comprises vertical posts at the four corners of the device, lateral bars secured between the corresponding posts, and longitudinal beams secured to the posts and bars, thereby forming the racks. Cages are suspended from the longitudinal beams. In such a rack device, the posts are provided at both longitudinal ends, which places obstacles in the way of access to the cages, and obstructs the handling of the cages, particularly the setting up and removal of the cages.
A belt conveyer is provided on each longitudinal beam which serves as a rack plate, in order to remove the remains of foods and excrement which drop from upper cages. The conveyer is disposed such that the belt slides upon the surface of the rack plate. However, the surface of the rack plate is made of a plurality of members which are welded together with respect to each other. Accordingly, many manufacturing steps are required to form the surface. In addition, the irregular surface causes increased friction for the belt.
Furthermore, it is difficult to detach and attach the rack plate and the belt conveyer, since the rack plate is secured to the lateral bars which are secured to oppositely disposed posts.
The belt conveyer is driven by means of a motor through means of a chain driving mechanism. The chain driving mechinism is complicated in construction and occupies a large amount of space. Generally, the motor os disposed at a position which is above the uppermost rack plate. Accordingly, the height of the motor mounting portion of the apparatus becomes large compared with other portions thereof, which renders the installation of a feeding system on the top of the apparatus difficult.
Further, the belt of the conveyer is washed at an end of the apparatus. However, in the conventional apparatus, the belt is not sufficiently cleaned.